Circular polarization is converted from linear polarization by splitting the incoming wave into two orthogonal wave vectors that are approximately equal in amplitude and 90 degrees apart in phase. The device that converts polarization from one state to another is often called a polarizer. Such a device may take the form of a waveguide component, a flat layered material placed above an antenna aperture, or as a multiport microwave device.
Some waveguide polarizers are coaxial polarizers. Coaxial polarizers often have dielectric pieces attached to the outer surface of a conductive inner tube of the coaxial waveguide. These dielectric pieces are responsible for creating the 90 degree phase difference in two orthogonal output modes of equal amplitude which leads to circular polarization. In prior art coaxial polarizers, the outer surface of a conductive inner tube of the coaxial waveguide has protrusions and the dielectric pieces have mating indents, by which the dielectric pieces are attached to the protrusions of the conductive inner tube. The conductive inner tubes with protrusions require complex machining processes. Likewise, the dielectric pieces that are mated to the protrusions require complex machining processes.